Method of automatic regulation of rectifiers and rotary converters.



No. 891,797. PATENTED JUNE 23, 1908.

P. B. OROOKER.

METHOD OF AUTOMATIC REGULATION OF REOTIFIERS AND ROTARY CONVERTERS.

APPLICATION FILED JULY 25, 1904. 4 SHEETS SHEET 1' W'rzwses: fizz/antar- @ZWMZ awaken No. 891,797. PATEN TED JUNE 23, 1908.

F. B. OROOKER.

METHOD OF AUTOMATIC REGULATION OF REOTIFIERS AND ROTARY CONVERTERS.

APPLIOATION FILED JULY 25. 1904.

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WM %6W%% 9 F Big? @LJWM/XM, Zyfl Ado No. 891,797. PATENTED JUNE 23, 1908.

'P. B. GROGKER.

METHOD OF AUTOMATIC REGULATION OF REGTIFIERS AND ROTARY CONVERTERS.

APPLICATION FILED JULY 25, 1904.

4 SHEETS-SHEET 3- Z fL ;/M% Qqakn No. 891,797. PATENTED JUNE 23, 1908.

P. B. GROOKBR.

METHOD OF AUTOMATIC REGULATION OF REOTIPIERS AND ROTARY CONVERTERS.

\APPLIOATION FILED JULY 25, 1904. 4 SHEETS SHEET 4 .7 7 Zara load,

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Wiizeszsasz [We/razor @WWZ %w/../ j j? mci'r FRANCIS B. ()ROCKER, OF .NEW YORK, N. Y.

METHOD OF AUTOMATIC REGULATION OF REGTIFIERS AND ROTARY CONVERTERS.

Specification of Letters Patent.

Application filed. July 26, 1904. Serial No. 218,053.

Patented June 23, 190% To all whom it may concern:

Be it known that I, FRANoIs B. CRocKEn, a citizen of the United States of America, and a resident of the city, county, and State of New York, have invented certain new and useful Improvements in Methods of Automatic Regulation of Rectifiers and Rotary Converters, 01' which the following is a specilication:

This invention relates to the automatic regulation of electric currents in conjunction with their conversion from alternating cur.- rent into direct current or from direct current into alternating current by any suitable rectifier or rotary converter.

The object of the invention is to secure automatic regulation by inductive action between the alternating current circuits as modified by the influence of the direct current by a method which required only simple and effective apparatus without moving parts. In this way it is possible to cause the voltage to remain constant or to rise with increase of load, and so overcome the drop of potential that usually takes place in the generator, transmitting lines, transformer, and other parts of the circuits when under load.

A typical form of the apparatus for practicing the herein claimed method comprises a magnetizable core with series and shunt coils connected to the alternating current leads through which current passes to the rectifier,

' current coil is divided into two portions oppositely wound on the two parts of the magnetic circuit, to neutralize inductive eil'ects, a rotary converter being used as a rectifier. Fig. 3 illustrates a modification of the preceding arrangement in which capacity is inserted in the shunt circuit. Fig. 4 illustrates a modification oi" the arrangement of Fig. 2 in which direct-current shunt coils are employed in addition to the direct-current series coils.

Fig. 5 illustrates a tri-phase alternator with a regulating apparatus similar to that of Fig. I

inserted in each of the three alternating-current leads from the alternator, and amercuryvapor rectifier. Fig. 6 illustrates a directcurrent generator, direct-current conductors fed thereby, a rotary converter, alternating-current circuits supplied with energy through the converter from the direct-current circuit and a regulating apparatus similar to that illustrated in Fig. 2. Figs. 7, 8 and 9 represent by vector diagrams the values and phase relations, at respectively zero, half, and full loads existing in a specific regulating apparatus constructed and operated accordin to my invention.

Referrin irst to Fig. 1, a single-phase generator feeds current to alternating current conductors A and B. These conductors supply energy through a rectifier C to direct current leads II I which deliver the energy to direct-current consuming devices such as storage battery cells P, motors F or lamps The rectifier or rectifying commutator consists of slip rings r 1- and a commutator s driven by a synchronous motor D which revolves in synchronism with the alternations of the current supplied from the generator. In series with one of the alternating current conductors A leading to the rectifier is a coil J wound on a laminated iron core E. A shunt coil N is also wound in the same direction on the core, and in the arrangement illustrated in this figure is connected at one end to a branch from the alternatin -current conductor A between the series coil and the rectifier. The function of this shunt coil is to induce a certain electromotive force in the .coil J acting in the alternating-current circuit in opposition to that produced by the generator G. Hence the actual alternating electromotive force supplied to the rectifier is less than that of the enerator. A third coil M is also wound on t e core, and is connected in series with one of the direct-current leads H. A choke coil T may also be placed in series in the direct-current circuit to prevent the flow of. any alternating current in this circuit which might otherwise be induced in the coil M.

The operation of the apparatus in regulating currents is as follows: When the load in the direct-current circuit is increased, for example by the insertion of additional lam s Q, motors F, or storage batteries P to he charged, the additional current flow in the coil M tends to saturate magnetically the core E so that the mutual induction between alternating-current coils N and J is reduced. The eileet of this reduction is to diminish the opposing electromotive force induced in the coil J by the coil N. The resultant voltage in the alternating-current circuit will therefore be increased, andthe voltage in the di root-current circuit which is supplied by the rectilied alternating current will likewise be increased. \Vhcn the magnetizing eil'ect of the direct-current coil M tends to saturate the core .10, the self-induction of the shunt coil N is reduced so that the current ilowing through it will rise in value. In order to prevent this rise from becoming excessive an inductance L, or a resistance it, or both, may be insertedin series with the coil N. If either or both of these have a considerable value compared with the self-induction of the coil N, then the variation of that selfil'idiuition will not cause too large an in crease of current in the coil. It is convenient to have this inductance or resistance adjustable, as shown so as to set or control the regulating ei'l'ects. In order that the initial opposing clectromotive'forcemay be exactly opposite in phase with respect to the electromotive force of the generator, the current in the shunt coil N should lag 90 behind the generator electromotive force. The opposing electromotive force in turn lags 90 behind the shunt current, thereby producing a total phase diil'erence of 180, or exact opposition. L in the shunt circuit is usually made large comparedwith the resistance B so that the current shall have a lag of approximately 90. Another advantage thus secured is the fact that inductance consumes no energy whereas resistance does. Owing to these phase relations the opposing electromotive force of the coil J results in a transformation of electrical energy from it to the shunt coil N. At no load this electromotive force has full value, but the'current being zero the energy is also zero. With any appreciable load-one-half for eXamplethe current is also one-half of the full value and the oppos ing electromotive force should then be approximately one-half of its initial amount in order that the resultant boosting effect (4 0. rise in voltageimay be neary proportional to the load. Under these conditions an amount of energy equal to the product of one-half of the full current by about one-half of the maximum opposing electromotive force (less the losses) is transferred from the series coil J to the shunt coil N. In consequence a larger. current and lower electromotive force than the generator produces may thus be supplied to the rectifier. As full load is approached, the main alternating current in the series coil J rises, but its opposing electromotive force falls owing to the magnetic saturation of the iron core by the direct-current coil M. Theoretically The reactanee due to the inductance this electromotive force should become zero at full load. Practically it still has a fraction of its original value since the magnetic saturation is not complete.

In the arrangement illustrated in Fig. 2 a core is employed having a double magnetic circuit, the two parts of which are indicated by the dotted lines 7 and p. The alternating-current coils N and J are wound on the part of the core common to both circuits, and the direct-current coil is divided into two portions M and M which are oppositely wound on the other two parts of the magnetic circuit. These coils are therefore balanced with respect to the alternating ilux induced by the alternating-current coils so that no alternating current is induced in the direct-currentcoils, and a choke coil in the direct-current circuit is unnecessary. This balance is less perfect when the .load increases, because the direct-current magnetization is in one direction and allows the alternating currents to vary the flux less in that direction than in the other, especially as saturation is approached. On the other hand, this saturation also tends to diminish inductive action, so that objectionable effects are largely avoided.

In the arrangement illustrated in Fig. 3, capacity K is inserted in the shunt circuit in lieu of the adjustable inductance L. The eil'ect of this capacity is to advance the phase relation of the current in the shunt circuit. Assumin that this advance has its maximum va ue of 90, the electromotive force set up in the shunt coil will lag 90 behind the current, hence it will be in phase with the impressed electromotive force. It follows therefore that the current in the series winding being in phase with the impressed electromotive force should be opposite in direction to that in the shunt coil. In other words, the two currents divide at their common junction as shown and flow in opposite directions around the central portion of the iron core in order that the electromotive force of the shunt coil may oppose the electromotive force of the series coil. Fig. 3 also shows that the shunt coil may draw energy from the alternating-current conductors directly, instead of after the alternating current has passed through the series coil as in the connections illustrated in the preceding figure. In this figure the shunt coil is su plied by a constant or falling electromotive i orce, and in Figs. 1 and 2 by a rising electromotive force.

The arrangement illustrated in Fig. 4, cmploys connections substantially as in Fig. 2, except that a direct-current shunt consisting of coils O and O is opposed to the series coils M and M. The direct-current magnetization thus obtained depends upon the difference between the ampere-turns in the two sets of coils so that the effect of variations in nection with load may'he accentuated. :Iilthimtiasiaitds also a'fact-that there-is an initial direct-current magnetomotive force at noload, while in-the preceding arrangement it is proportional'to the load.

In the arrangementof Fig. .5, the invention-is applied in connection with amercur-yvapor rectifier, such as the CoopenHewi-tt. rectifier. The regulating devices I constituting my invention are inserted-inweach of .the'

three alternating-current leads from a suitable source-ofthree-phase current .G'. The currents through'the series coilsJ JJ m lod to the positive electrodes E E E inithe-.up-* per part of the mercury-vapor rectifier. The currentsthrou -h the shunt coils N N N return to'the neutra pointof the three: hase generator. The direct-current leads: I are connected respectively =-to the neutral point A direct current enerator S feeds currentto-direc't-current eads H I. These conductors suppl energy through -a.-rotary converter to a tern-ating-current leads A. B which deliver the energy -to consuming devices either directly or-through transformers. The" regulating apparatus is as described in con i 2, and consictsof aseries coil J connecte in one of the alternatingcurrent leads, a shunt coil N wh-ichwis connected across the alternatingcurrent leads, and a two-part direct-current series "coil M M inserted in one-of the adirect-current leads through which direct current reaches the rotar converter. As=betore,-the*shunt coil N in wees an initial oppos' -electromo, tive force in the-series coil J of It e'alternata ing-current circuit, producing :a resultant electromotive force less-than that-given out by the converter. The direct-current in the coils M M, increasing direotlywiththe-load, tends to saturate magnetically ithe-core and suppress the --opposing electromotive. force, thus automatically raising the resultant electromotive force of the alternatingcurrent circuit A B, in accordance withmy invention.

In order toshow the phase relations exist ing in my automatic regulating device and to illustrate how it'may be designed to fulfil practical conditions, the following example is given: The arrangement ofapparatusand connections illustrated in-Fig. 2 is adopted, and the central portion of the iron coreEis assumed to be '-11 X8" =88-square inches, each end portion 5 being half as large or .pliedtothe rotary-converter (Oin Fig 5* X8 M isquarc inhes because there :are two magnetic circuits. The maximum-flux through'thecontnalqpart may be taken as 88 X87,000 =7;656,0001ines, ocin 87,000 lines per square inch or 13,500 lines per square centimeter. Each magnetic circultp or vy is Q0. inches in l thand requires about 25 :ampere-turnsh'ger mch or 40x25 =1-,000 ampere-turns .in e (shunt r coil N to produce a fiuxdensity of 13,500. .Ata ire uenc of 60 this flux willset up about 20 v0 tse ective-electromotive force in each turn of the series=coil J, so that .5- turns will produce 100 volts in-opposition tothe electromotive force oflthe alternating-current generator G. This opposing .electromotive *force is representedh the line 0 c inFi 7 -and the .genorator o ectromotive force y the line 0 g. Assuming the latterz-to be 050 volts theresultant alternating electromotive-foroe sup- 2) IS 550 voltsatno load, being represents by 0 1- in-Fig. 7.

I At halfload the series alternating current coil vJ will-carry 280 ampercs 1.1: nqum.) so that its magnetomotive iorceis280-X 5 =1A00 ampere-turns, and is in-phasewiththe generator electromotive force as indicated by the line 0 s in Fig.8. This combined with the shunt ampere-turns o. t which areassumed to have increased-to 1,500, produces a resultant cm of 2,060 ampere-turns, being the total alternating magnetomotive force. Assuming 1-3 turns in each of the direct-current coils M M and acurrent of 138 am cres,=the magnetomotive-force of each coil is 138 X13 or approximatelyh800' am re-turns. This heingv cons-tantandin one direction, the alternating mag-netomotive force combines with it to giveamaXimu-m of 1,800 +2,050 =3,850 airmen-turns and a minimum of-1-,800 2,050 -250.a'mpere turns. The variation in 'fiux thus produced willset upin the series alternating-current coil J anelectromotive force of about 82 volts lagging 90-with respect to the-phase ofthe alternating magnetomotive force as represented by the line 0 c iniFig. 8. This electromotive force acting with that of the generator 0 g gives a result:

ant 0 1' of 590 volts being/L0 volts higher. than at:- zero load. I

At full load the series alternating-v current coil -J carries 560. amperes, giving 560. 5=2,800 ampere-turns, indicatedv by the. line '0 s iii-Fig.0. This combines with 0 t, the shunt magnetomotive force, which has become 2,000 ampere-turns and gives the resultant 0 an of 3,440 ampere-turns for the .total. alternating ma netornotive force. The

direct-current at f I load is 276amperes giving :a magnetomoti-ve force of9276 13 or approximately 3,600 .am' re-turns in each coil M M. This in com ination' with the alternating magnetomotive force produces :a 'maximuin of 3,-600+3,440 =7 ,040

and a minimum of 3,6003,440==160 ampere-turns. The corresponding flux variation generates an alternating electromotive force of 48 volts 0 c in the series coil J which is combined with 0 g the generator electromotive force to form the resultant 0 7 amounting to 625 volts, being 35' volts greater than at half load, the rise being approximately proportional to the load. Increase in the shunt current and ampereturns is due to the decrease in the inductance of that circuit resulting from the partial saturation of the iron core by the directcurrent coils M M. This ell'ect may also be produced or increased by connecting the shunt coil N beyond the series coil J, as shown in Fig. 2 so that it is fed by an electromotive force that rises with the load. The presence of resistance in the shunt circuit will tend to reduce the lag of the current. In Fig. 2, for example, an increase in the resistance R and a diminution of the inductance L will have this effect; that is, the angle between the shunt-ampere-turns 0 t and the generator electromotive force 0 9 becomes less than 90. Other things being equal, this will decrease the effect of the opposing electromotive force 0 0. Hence by varying the inductance L, or the resistance R, or both, and by altering the relative number of turns in the several coils, the regulating action of the apparatus may be set or adjusted to suit difi'erent conditions. In the particular example cited, the generator supplies 650 volts eiiective and 560 amperes maximum, or 397 amperes effective, which gives 258 kilowatts at full load, and the volume occupied by the regulating device is only about 3 X 1 X 1 =5 or, 4 cubic feet. In the example given, it is not attempted to state the voltages, currents, etc., with exactness, because they would depend upon the permeability of the iron core and other practical conditions. Furthermore it was pointed out that there is a transformer action between the shunt and the series alternating-current coils, so that the current supplied to the converter or rectifier is more and the voltage less than in the generator.

I do not claim in this application the apparatus herein shown as that is claimed in my application filed April 4, 1908, S. N. 425,110 as a division hereof.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of regulating electric circuits which consists in introducing in the main circuit inductance set up by the combined effects. of alternating and direct currents, which latter constitutes the load current, substantially as described.

2. The method of regulatin electric circuits which consists in introducing in the main circuit inductance set upby the combined effects of alternating and direct currents, one of which currents is derived from the other, substantially as described.

3. The method of regulating a direct current circuit, which consists in generating an alternating current, rectifying or converting the same into direct current and introducing inductance set up by the combined effect of the alternating and direct currents, substantially as described. 4. The method of regulating electric circuits which consists in introducing mutual inductance set up and controlled by the combined effects of alternating and direct currents, substantially as described.

5. The method of regulating electric circuits which consists in introducing mutual inductance in an alternating current circuit, and in controlling this inductance by means of a direct current obtained by rectifying or converting the alternating current, sub stantially as described.

6. The method of regulating electric circuits which consists in setting up an inductive electromotive force by mutual induction in addition to the electromotive force therein and in automatically varying the phase relation of the former with respect to the latter by the resultant inductive effect of two or more currents, substantially as described.

7. The method of regulating electric circuits which consists in setting up an auxiliary electromotive force by mutual induction in addition to the impressed electromotive force and in automatically varying their phase relation by the resultant inductive effect of alternating and direct currents, substantially as described.

8. The method of regulating electric circuits which consists in setting up an auxiliary electromotive force by mutual induction in addition to the impressed electromotive force and in automatically varying their phase relation by the inductive effects of two currents one of which is derived from the other, substantially as described.

9. The method of regulating the electromotive force of a direct-current circuit automatically with the load, which consists in generating an alternating current, setting up in circuit therewith by mutual induction an o posing electromotive force, rectifying the a ternating current, and reducing the opposing electromotive force through the agency of the rectified direct current, substantially as described.

10. The method of regulating the electromotive force of a direct-current circuit automatically with the load, which consists in generating an alternating current, setting up in circuit therewith an opposing electromotive force through the agency of an iron magnetic circuit, rectifying the-alternating current, and reducing the opposing electromotive force by partially saturating the magmotive force of'a direct-current circuit autoin a series coil in circuit therewith an opposnetic circuit by the action of the rectified and reducing the opposing electromotive direct current, substantially as described. force by partially saturating the magnetic 11. The method of regulating the electrocircuit by the action of a direct-current coil, substantially as described. maticallywith the load, which consists'in city, N. Y.,

Signed byme at New York generating an alternating current, setting up this 14th day of Jul 1904.

ing electromotive force by the inductive FRANCIS C K R' action of an alternatin -current shunt coil- Witnesses: through the agency 0 an iron magnetic HUGH H. SENIOR, circuit, rectifying the alternating current, ALFRED E. FROST. 

